I feel like this line was crossed decades ago. As a child I saw the summary execution of Nguyễn Văn Lém on television. The suicides of Christine Chubbuck and Budd Dwyer, among others, were shown on TV too. Media in general has brought this kind of imagery into our homes for a long time.

I don't know what the answer is, when the problem is humanity. Social media platforms can do their best to limit what kinds of videos get posted, preventing the upload of content based on similarity to block-listed items, and moderators removing reported content, but beyond that I don't know...

This isn't anything new. Media has always sensationalized events like this, the only difference is how often it happens and how sensationalized it gets. I think social media plays a large roll in this, as an individual who might be considering committing these crimes, the almost guaranteed attention you can grab is a strong motivator for tons of people.